Production of hydrocarbon-oxygen compounds



' Jan. 9,1940. J. c, WALKER 2, 8

- PRODUCTION OF HYDROC'ARBON-OXYGEN COMPOUNDS I Filed June 18, 1935 GNOOdNQD NBQAXO NOQHVDOUOAH Ombl'l \NTERCHANGER REACTION VESSEL LIQUID HYDROCARBON OXYGEN I COOLER scaussaa INVENTOR \JOHN C. WALKER sv ATTOREYI HYDROCARBON GAS GAS AND moaocnneou oxveeu Patented Jan. 9,1940

COMPO UNDS- John Charles Walker, Bartlesville, 0kla., assignor to. Cities Service Oil Company, Bartlesville, 0lrla.,'a corporation of Delaware Application June 18,

1935, Serial No. 21,202

In Romania and Mexico, May 1'1, 1927 6 Claims.

1 This invention relates to the production of formaldehyde, methanol and other liquid hydrocarbon-oxygen compounds by the partial oxidation of gaseous and low boiling liquid aliphatic.

improvement on the inventions described in my.

u copending applications Serial .No. 192,077, flied May 1'7, 192'7; Serial No. 211,888, flied August 10, 1927, U. S. Patent No. 2,007,115; and Serial No. 424,170, filed January 29, 1930, U. S. Patent No. 2,007,116.

The primary object of the. present invention is to provide an improved process for manufacturing liquid hydrocarbon-oxygen compounds by the partial oxidation of gaseous and low boiling liquid aliphatic hydrocarbons.

A more particular object of the invention is to provide an improved process for treating gaseous and low boiling liquid aliphatic-hydrocarbons-whereby large yields of liquid hydrocarg hon-oxygen compounds of high quality and commercial value are obtainable.

' With these and other objects and features in view, the invention consists in the improved method for producing hydrocarbon-oxygen com- 3' pounds from gaseous and low boiling liquid aliphatic hydrocarbons which is hereinafter described and more particularly defined in the claims.

The improved process will be hereinafter more it particularly describedwith reference to the accompanying drawing, in which:

The figure illustrates diagrammatically in side elevation, with parts in section, the preferred arrangement and design of apparatus employed Al in carrying out the process.

The process of the present invention will be hereinafter more particularly described with reference to the treatment of natural gas. Nevertheless it will be understood that the process of 60 the present invention is applicable to the treatment of all gaseous and low boiling liquid aliphatic hydrocarbons and-may be used in oxidizing pure hydrocarbons such as'ethane, propane, butane, pent'ane, ethylene, propylene, butylene or ll higher boiling liquid hydrocarbons, or mixtures of any of these such as occur in oil refinery gases and gasoline. Application of'the process to the hydrocarbons referred to will yield formaldehyde, methanol and other valuable hydrocarbon-oxygen products. By employing an operating pressure in the range of 200 to 350 pounds per square inch a product containing a large proportion of formaldehyde is obtainable, and by increasing the operating pressure to 750 pounds per square inch the alcohol content of the product is considerably increased at the expense of a drop in the proportionate yield of formaldehyde.

An illustrative example of an application of the process to the treatment of natural gas will now be described:

Natural gas of the approximate composition: methane 54.2%, ethane 15.7%, propane 11.8%, butane 3.7%, nitrogen 13.6%, and oxygen 1%, is conducted. from a source of such gas under high pressure through a meter it, from which a measured volume of the gas is passed by a pressure regulating device it into pipe line ll at a substantially constant pressure of about 300 lbs. per square inch. The gas is conducted through the valved connection ii at a regulated flow rate into theouter phase of the cold end of a U-shaped horizontally disposed heat interchanger it. The temperature of the gas at this point is normally within the range 50100 F. In passing through the interchanger the gas is preheated to a temperature of approximately 700 F. by heat interchange with hot treated gas passed through the inner phase of the interchanger. A by-pass connection i9 is provided between the two arms of the interchanger about half-way of its length so that the flow of gas through the outer phase of the interchanger may be short-circuited therethrcugh if desired. From the hot end of the outer phase'of the interchanger the gas is discharged into a pipe 20 comprising an inlet connection for reaction vessel 22. Simultaneously air, in measured volume and also under a pressure of about 300 lbs. per square inch, is introduced into the pipe 20 from an air pipe 24' through a mixing device 26. Device 26 comprises a plurality of very small orifices opening from pipe 24 into a Venturi throat portion 28 of the pipe 20, whereby small high velocity jets of air are introduced into the pipe 20 at right angles to the direction of flow of gas therethrough, so that a thorough and rapid mixing of the hydrocarbon and air is effected-at this point. The mixture of hot gas and air thus formed, preferably containing less than 10% by volumefof oxygen, is conducted through a pipe riser 2 to the top of reaction vessel 22 and is releas into an annular reaction space 30, formed around riser 29 and below cone 3|. space 30 is preferably filled with a contact substance or catalyst, such as pumice having a mixture of aluminum phosphate and copper oxide deposited thereon. a

For treating hydrocarbon gas of the type forming the subject of this example, the amount of air introduced into pipe 26 through nozzles-'26 is preferably controlled to maintain a maximum temperature in the reaction zone 36 in the neighborhood of 840 F. to 880 F. The temperature thus maintained in the reaction zone (by heat developed as a result 01' exothermic reactions between the hydrocarbon and oxygen) is dependent not only on the nature and amounts of the reacting constituents, but also on the character of the reaction vessel and the rapidity with which heat is removed therefrom by radiation and in the form of sensible heat carried out by the products of the reaction.

- The hydrocarbon-air mixture enters the reaction chamber at the top of the filling of catalyst or contact material, and passes downwardly therethrough and thence out through an outlet connection 32 at the bottom of the tube 22. Outlet 32 is located below a supporting grid 33 on which rests the catalyst or contact filling. From connection 32 the hot reaction mixture, containing the liquid hydrocarbon-oxygen products formed in the reaction zone in vapor form, passes through the inner space of the heat interchanger IB wherein it is cooled to a temperature of about 250-300 F. by heat interchange with the hydrocarbon passing through the outer space of the interchanger on its way to the reaction chamber. Some of the liquid hydrocarbon-oxygen products condense in the interchanger, and for this reason the interchanger and the connections leading from the discharge side of its inner phase are preferably constructed of corrosion resistant material, such as brass and are arranged to facilitate rapid draining oif and collection of the condensed liquids. From the cold end of the interchanger the reaction gases and condensed vapors denser.

of liquid hydrocarbon-oxygen condensate is recovered in a trap 4| at the bottom of manifold 40 and in a separator 42 at the outlet of the con- Separator 42 is equipped with internal helically arranged baflies 43 whereby a whirling cyclone motion is imparted to gas passing therethrough and liquid particles are thrown to the outside and collected in a trap 44. It will be noted that the arrangement of the condenser and connections is such that the liquid condensate is kept in contact with the gas from which it is condensed and flows along with the gas stream to the separator and traps at the outlet of the condenser. By this arrangement more, eillcient condensation is secured because the heavier products Theof higher boiling point are contacted with the gas up to the time that it leaves the condenser, such heavier products aiding in the removal of lower boiling fractions by an absorption or scrubbing action.

From water'cooled condenser 36 and separator 42 the treated gas, which still contains recoverable vapors of normally liquid hydrocarbon-. oxygen products, is led through a pipe 46, trap 48 and valved inlet pipe 50 into the hot end of a cold interchanger 52. The temperature of the gas entering interchanger 52 is approximately 80 F., and in passing through this interchanger the gas is precooled to a. temperature of approximately 30 F. to 35 F. Any additional hydrocarbon-oxygen product condensed in the interchanger 52 is trapped in a separator 54 at the discharge end of the interchanger from which it may be passed through pipe connections 56 and 58 to storage,

From separator 54 the gas passes through a connection 60 into a cooler-scrubber 62. This cooler-scrubber comprises essentially a horizontal cylindrical tank which is kept about half filled with liquid hydrocarbon-oxygen condensate introduced through a pipe 64 from water cooled condenser 36 and separator 42. The coolerscrubber unit 62 is provided with refrigerating coils 66 and with bailles 68, 69 and 10, whereby gas admitted at the end of the unit through the connection 60 is caused to enter the interior of the scrubber at high velocity below the surface ll of the liquid condensate contained therein, the cooler tank and cooling surfaces and bafiles being so arranged that the entering velocity of the gas causes an active circulation of the mixed gas and liquid from end to end of the tank. Thus the gas after admission near the point 72 at the bottom of one end of the tank flows to the opposite end of the tank through the liquid and then returns to the inlet end of the tank in the upper part thereof. The liquid condensate in the tank 62 is cooled to a temperature of approximately 20 to 25 degrees F., whereby further light hydrocarbon-oxygen products are recovered from the gas by condensation at the lower temperature and by absorption in the cold less volatile fraction obtained in the water cooled condenser 36, thus simultaneously enriching the water cooled condenser condensate. The cold treated gas is then passed through neck 13 at the top of the tank 62 and through helically arranged baflies 14 into an annular space 16 of a separating dome 18 overlying tank 62. In passing through bafiles 14 into chamber 16 a whirling movement is given to the gas whereby substantially all liquid entrained in the gas is thrown out; the dry gas then flowing through a cylindrical fine mesh screen 19 into an outlet chamber 80 at the top of dome 18, from which it passes by a connection 82 into and through the interchanger 52 in heat interchanging relationship with the vapor-carrying gas on its .way to the cooler-scrubber 62. The temperature of the dry gas is raised in the interchanger to within 3 to degrees of that at which it enters the devaporizing system comprising interchanger 52 and cooler-scrubber 62.

In this condition the gas is either delivered to the treated gas pipe line 84, or may be recycled through a recompresscr 81, through connection 86, and valved recycle connection 88, or may be passed with or without recompression, by a pipe 90 into and through another heat interchanger l8 and treating, chamber 22 wherein it is subpipes 88 I to maintain a constant level of .the liquid in the:

a aaeaa and to another similar gas devaporizing unit (not shown) through pipe 84.

The vapor content of the gas leaving the gas devaporizing unit is normally low enough so that no condensation takes place in the exit pipe lines, even'when the proportion of dry treated gas to untreated gas in such lines is in the neighborhood of 20% to 30%. This-dry condition of the pipe lines on the delivery side of the devaporizing unit prevents internal corrosion of the lines.

There is a continual flow of liquid condensate from water cooled condenser 38 into cooler-scrubber 82, and a considerable additional volume of liquid is condensed and absorbed in the coolerscrubber. This liquid is removed by overflow and I88 to storage in suflicient quantity cooler-scrubber 82. The tail gas from the flnal stage of treatment is finally discharged into-the main gas discharge line 84.

As previously indicated, the invention contemplates both single and multl-stage treatment of the hydrocarbon, and either or both recycle and series operation of the treating units during multista'ge treatment. During recycle treatment the treated gas from treating chamber 22, for example, after having passed through hot interchanger I8, water-cooled condenser 88, cold interchanger 52, cooler scrubber 62, and back through the outer phase of cold interchanger 82, is passed by pipe 88 into recompressor 81 where its pressure is again raised to approximately the .pressure of the hydrocarbon originally admitted to the treating chamber from pipes I4 and I8. From recompressor 81 the recycle gas is reconducted by connection 88 back through connection I8, heat interchanger I8, and air mixing passage 28 wherein a fresh supply of oxygen is admixed therewith, and thence again into treating chamber 22. Tail gas is removed from the system through pipe 84 in sufficient quantity to maintain a desirable substantially uniform pressure and to keep the inert nitrogen content of the ,hydrocarbon gas treated suflilciently low, and the.hydrocarbon content sufficiently high, for the recovery of suitable yields of liquid hydrocarbon-oxygen products. A measured volume of raw untreated hydrocarbon may be added to the recycled gas from main I4 and connection I8 as make-up. The make-up" hydrocarbon may be a rich gas, such as propane-butane mixture or a propylenebutylene mixture.

Under the operating conditions specified, some decomposition and polymerization or condensation reactions occur, particularly when treating olefin hydrocarbons, producing liquid hydrocarbons (chiefly oleflns) which have higher boiling points than any of the hydrocarbons treated in the process. These hydrocarbons are liquifled, along with the liquid hydrocarbon-oxygen compounds, in the cold devaporizing equipment. The v If desired a certain amount of' 'ing bubble cap tower operatingunder substanuid hydrocarbon-oxygen products per unit volhydrocarbon-oxygen-compounds are water soluble, and can therefore be separated from the oil soluble hydrocarbons by simple gravity separation preferably under pressure. A solvent for the hydrocarbon-oxygen compounds may be used in conjunction with the gravity separation step. The hydrocarbons may be separated into high and low-boiling fractions in a pressure separator I82. The pressure separator I82 is a fractionattially the same pressure as the other apparatus elements previously described. The liquid hydrocarbon fraction is introduced through pipe connections I84 and I88 into the tower I82 at about its mid-point vertically. The tower is provided with a water cooling or refrigerating element I88 atits top and with a heating element II8 nearits base. The light hydrocarbon liquids may be taken off as vapors through a pipe H2 and returned by a pump I and vaporizing chamber H8 to the treated gas line 88 for use as "makeup" hydrocarbon. The heavier hydrocarbons and any hydrocarbon-oxygen product which collects at the base of the tower are withdrawn through I a connection H8. 1

- Partial oxidation treatment of natura the aforementioned composition with abc iufi fo f by volume of air at the pressures and temperatures indicated, has yielded a liquid hydrocar bop-oxygen aproduct of the following approximate composition: acetaldehyde 5 to 6 per cent, by weight, methanol 34 to 36 per cent by weight formaldehyde 20 to 23 per cent by weight; to gether with varying amounts of water and higher alcohols, aldehydes, acetals, esters, ketones and other hydrocarbon-oxygen compounds. The formaldehyde is recovered in the form of an aqueous solution having a formaldehyde concentration I of approximately 30. to 4 0 per cent by weight. 4. The composition of the tail gas produced by a single passage of the aforesaid natural gas with air through a single treating unit (comprising reaction tube, water cooled condenser and coolerscrubber) has approximately the following composition: methane 47.9%, ethane 14.5%, propane. 11.1%, butane 3.2%, carbon monoxide 1.7%, hydrogen 0.2%, nitrogen 20.8%, oxygen 0%.

In order to obtain a maximum recovery of liqume of aliphatic'hydrocarbon gas treated, it is necessary to react the hydrocarbon gas with a greater volume of air than can be satisfactorily added to the gas in a single treatment, because of the highly exothermic character of the reaction. For this reason the tail gas resulting from the first treatment of the raw aliphatic hydrocarbon gas in a treating unit comprising an individual reaction tube together with its gas devaporizing train, is admixed with an additional permissible volume of air-or oxygen and again subjected to partial oxidation reactions in the same or another reaction tube, followed by recovery of the liquid partial oxidation products formed in the same or preferably another devaporizing train. This step by step or stage treatment of the gas may be continued in successive stages so long as the tail gas from the last stage of treatment has sufllcient hydrocarbons present in its composition to yield a liquid hydrocarbon-oxygen product of'value sufllcient to pay for the treatment. As indicative of the composition of successive tail gases resulting from series treatment of the gas with approximately 78 4 10% of air in each stage, the following analyses are cited:

Composition of untreated natural gas Balance chiefly CO and CO2.

Tail gas #2 resulting from treatment of tail as #1 I Per cent Methane 19.7 Ethane; 10.2 Propane 9.7

Butane i 2.9 Nitrogen 24.6

Balance chiefly CO and CO2.

. The results of a continuous recycle run carried out at 250# pressure with a combination aluminum phosphate-copper oxide catalyst maintained at a temperature of 860 to 870. F. were as follows:

Volume ratio of fresh hydrocarbon gas to 17.5 total air used Volume ratio of fresh hydrocarbon gas to 17.5 recycled tail gas Volume ratio of fresh hydrocarbon gas to 17.5 discarded tail gas 36.0 Untreated gas composition:

CO2 0.2 Oz 0.2 CH4 57.9 CzHs 16.1 Cal-Ia 11.8 C4H10 3.4 Residue (N2 by difference); 10.4

Discarded tail gas composition: CO2 3.00 Oz 0 CH4 25.34 CaHs 6.88 CaHa 1.55 Unidentified hydrocarbons 2.22 CD 4.98 Hz 2.36 Residue 53.67

Crude hydrocarbon-oxygen products formed:

A. Yieldapproximately 2.5 gals/M cu. 'ft. of-

fresh hydrocarbon gas used; BL Composition-'- 5.43% by weight CHaCHO, 12.04% 1301-10, 30.71% CHaOI-I, 51.80% E20 (by difierence).

The content of formaldehyde in the product 2,1se,oss 1 1 1000 cu. ft. of gas treated varies considerably with the composition of the reaction mixture and with pressure and other controlling factors. A natural gas having upwards of 20% by volume of ethane, propane and butane in its composition normally yields a much'larger volume of formaldehyde than a gas containing a large percentage of methane and a smaller percentage of higher parafiine hydrocarbons. The yield of formaldehyde is favorably affected by the use of a substantially constant pressure of approximately 200 to 350 lbs. per square inch in the reaction chamber, and also by the use of moderate reaction temperatures (preferably below 1000 F.), high velocity throughout, such that each unit volume of the reaction mixture passes through the high temperature reaction zone in a period of between one fourth second and four seconds and preferably less than two seconds, and by the use in the reaction chamber of a contact material such as the aluminum phosphatecopper oxide mixture hereinafter more fully described. 1 g

A lean recycle gas which contained a large proportion of nitrogen and only relatively small amounts of hydrocarbons which, however, consisted chiefly of propane and butane, and having a unit heating value in the neighborhood of 400 B. t. u. per cubic foot, gave on treatment good yields of liquid product having a satisfactory formaldehyde content; whereas another gas containing relatively small amounts of ethane, propane and butane and large amounts of methane with little inerts, and having a unit heating value of 1000 B. t. u., treated in exactly the same manner gave very low yields 'of formaldehyde, but relatively much higher yields of methanol and acetaldehyde. In treating a lean gas containing only small amounts of ethane, propane, butane, or other aliphatic hydrocarbons than methane by the present process it is advantageous to admix therewith an enriching agent containing large proportions of ethane, propane, butane, ethylene, propylene,-butylene, where' such enriching hydrocarbons are available at a price warranting their conversion to liquid hydrocarbon-oxygen products.

One of the most importantfeatures of the present process is that of control of the temperature which is maintained in the reaction zone. This temperature is not allowed to rise above 1000 F. or fall much below 550 F., and is preferably maintained in the neighborhood of 800 to 900 F. in treating natural gas, though somewhat lower temperatures may be used in treat ing a reaction mixture having a high content of hydrocarbons having two or more carbon atoms in the molecule such as propane, butane, propylene, butylene and pentane. The control of the temperature is efiected chiefly through the amount of oxygen or air added to make up the .reaction mixture, and through the degree of preheat which is imparted to the reaction mixture. The degree of preheat can be varied by varying the proportion of hydrocarbon which is passed through the heat interchanger units on the inlet side of the reaction zone, and through by-pass 19. The hydrocarbon not so preheated may be by-passed through a pipe H8 directly to the inlet tube of the reaction chamber. The hydrocarbon or hydrocarbon containing gas under treatment is normally preheated to a temperature within 100 F.-200 F. of the maximum reaction temperature. In other words, gas entering the reaction zone is normally preheated to 2,1se,eae v is initiated and partially completedin this open a temperature within the aproximate range of 400 F.-1000 F. air or oxygen is usually added to the reaction mixture in the proportions of .8%-10% by volume of oxygen per volume of hydrocarbon or gas under treatment.

The invention is not limited to the use of catalysts or contact substances. yields of the product are-obtainable without the use of any catalyst or contact filling in the reaction chamber. However the reaction progresses more smoothly and is much more easily con- .trolled when a contact material or filling is employed in the reaction chamber. The preferred contact filling consists of a pumice base having approximately 3.1 lbs? of aluminum phos- 'phate and approximately one-half pound of copper oxide deposited thereon per cu. ft. of catalyst mass. the aluminum phosphate being considered an excellent dehydration catalyst, while the copper oxide-is a well known catalyst generally conthis type that the fouling of the reaction chamber with carbon appears to be inhibited thereby. Use of a catalyst or contact filling of this preferred type has other advantages such as:

. 1. Tendency to stabilize the reaction and render it much less subject to adverse qulck changes in other operating conditions, and to promote rapid recovery from the effects of adverse changes of long duration. Y

2. Actual increase in formaldehyde content of the liquid product.

3. An increase in the yield of liquid product from each unit of the treating apparatus.

4. A marked decrease in the time required to bringthe apparatus to a satisfactory producing basis after a shut down.

5. A liquid product having a much sweeter odor than that obtainable with other contact substances which have been tested.

6. Assurance of complete combination of the free oxygen content of the reaction mixture. The use of this aluminum phosphate-copper oxide catalyst and the maintenance of the reaction mixture under a substantially constant operating pressure, permits the use of a higher rate of gas fiow through the reaction zone and consequently results in an increased unit plant capacity and increased eificiency. The optimum time of contact of each unit volume of the reaction mixture with the catalyst, or in the reaction zone, has been found to be in the neighborhood of one to one and one-half seconds. In place of the preferred catalyst other metals and non-metals and their oxides may be used, either singly or in combination, reference being hereby made to my aforementioned applications for examples. A mixture of an oxide of a metal of the 1st or 2nd groups of the periodic table, such as copper, zinc or silver oxide, with a phosphorous acid salt or oxide of a metal of group 3, such as aluminum or thallium phosphate or oxide, in the relative proportions present in the preferred catalyst, makes a particularly satisfactory contact substance.

The design of the reaction chamber illustrated is such that after the reaction mixture is formed by mixing hydrocarbon gas and air, the mixture passes through an open passage (tube 29 and space under cone 3!) of considerable volume and at or near the reaction temperature before coming into contact with the catalyst. It has been Satisfactory This catalyst is of the mixed type,-

space, the reaction being thereafter. completed and apparently modified in contact with the catalyst bed. Better yields and quality of liquid hydrocarbon-oxygen product are obtained when the reaction mixture passes initially through this heated free space than when no free space is provided separating the catalyst bed and the point at which the hydrocarbon and air are mixed to form the reaction mixture. Normally the proportions of the treating chamber and of the catalyst bed are such that with a total time of sojourn of the reaction mixture in the high a temperature reaction chamber of about 2 seconds for example, the mixture is in contact with the catalyst about halfthat time, and is subjected to temperature conditions favoring reaction for about second before coming in contact with the catalyst. When a catalyst filling is used in the reaction chamber, the volumes of catalyst space and of free open space preceding the 'catalyst should be so proportioned as to provide a time of sojourn of the reaction mixture in such open space at substantially reaction temperatures of at least 0.1 second before contact with the catalyst, out of a total time of sojourn of the reaction mixture at or near the reaction temperature of not to exceed 2 seconds.

Satisfactory operation of the plant is possible at pressures at and below 200 lbs. per square inch, although it has not been found possible to secure commercial yields of liquid organic product when using pressures below 100 lbs. per sq. inch in the treatment of natural gas. A rich gas or vapor having a relatively high content of propane, butane, pentane or heavier hydrocarbons may be treated at low pressures much more satisfactorily than can a lean gas containing chiefly methane. In general the yield of liquid product, and up to a certain point also the' quality, increases proportionately with an increase in pres-- sure. Furthermore the reaction is always more stable at higher pressures. But pressures above 400 to 500 lbs. per square inch are more favorpercentages of, ethane, propane and butane re-.

quired only about of air. However, a lean gas containing propane and butane in small proportions only, together with a large quantity of nitrogen or other inerts, may require large percentages of air or oxygen in order to maintain satisfactory reaction temperatures. Thus it was found in one case that a lean tail gas required oxygen in the proportions of 59% by volume of the hydrocarbon content of the gas, in order to maintain the desired reaction temperature, because of the large amount of inert gaspresent in the reaction mixture. The amount of oxygen employed should be less than 10 per cent by volume of the total reaction mixture or mass (including hydrocarbon and nitrogen, C0, C02, hydrogen and the like).

- The liquid organic reaction products of the can collect and stand. Any condensate formed in I treatment, particularly formaldehyde, are rather readily decomposed and polymerized. The decomposition of formaldehyde is catalyzed by iron and is hastened by an apparatus design wherein the liquid products of the partial oxidation reaction are cooled slowly and allowed to stand in contact with iron and with hot gases. Accordingly, the preferred apparatus for carrying out the present process is designed to allow rapid removal of the reaction products from the high temperature reaction zone, rapid cooling and separation of these products, and avoidance of traps for condensed liquid between the reaction chamber and the hot inlet side of the water cooled condenser, wherein the liquid condensate the heat interchanger on the discharge side of the reaction chamber is not allowed to collect and stand but is carried along with the gas stream through the interchanger into the water cooled condenser and then cooled as rapidly as possible in the condenser. Removal of liquid at this point is rapidly accomplished. The cold end of the heat interchanger and the condenser and connections are also preferably constructed of material which is not a catalyst for formaldehyde decomposition, examples of such materials being copper andbrass. The water cooled condenser is designed to so. far as possible prevent fractional condensation, which is conducive to corrosion and to inefiicient removal of the lower A vapor pressure ends carried in the gas. By efiecting the separation of the entire condensate from the gas at the point where cooling of the gas has reached approximately normal atmospheric temperature, namely in the water cooled condensers, a more complete recovery of co-ndensible vapors is accomplished and the absorptive power of the higher boiling for the lower boiling vapor ends is utilized to the fullest extent. In the type of condenser illustrated there is a continuously downward passage of any previously formed condensate in continual contact with the gas in continuous tubes until separation takes place in the condenser traps and separators.

The use of the crude liquid condensate obtained in the condenser as the scrubbing and absorbing medium in the cooler-scrubber element of the devaporizing system is an important feature of the process whereby the following result are efiected:

1. Further enrichment of the crude condensate recovered in the water-cooled condenser.

2. Recovery of additional valuable liquid oxidation products from the gas, with consequent increased total .production of liquid products.

3. Removal of all but small traces of irritating odors and corrosive acids and the like from the tail gases.

The invention having been thus described, what is claimed as new is:

l. A process of treating a normally gaseous olefin hydrocarbon to produce valuable liquid products, which comprises subjecting the olefin at temperatures in the range of 550 to 1000 F. to the action of a mixed solid catalyst comprising aluminum phosphate together with an oxide of a heavy metal belonging to groups 1 and 2 of the periodic-table.

2. A process of treating a normally gaseous olefin hydrocarbon to produce valuable liquid products, which comprises subjecting the olefin at temperatures in the range of 550 to 1000 F. to the action of oxygen in the presence of a mixed catalyst comprising aluminum phosphate together with an oxide of a heavy metal of groups 1 and 2 of the periodic table.

3. A process of treating a normally gaseous aliphatic hydrocarbon toproduce valuable liquid products, which comprises subjecting the hydrocarbon at a temperature in the range 550 F.- 1000 F. and at a pressure above pounds per square inch to the action of a mixed catalyst comprising aluminum phosphate together with an oxide of a metal taken from the group consisting of copper, zinc and silver.

4. A process of treating a normally gaseous olefin hydrocarbon to produce valuable liquid products, which comprises subjecting the olefin at temperatures in the range of 550 to 1000 F. and pressure above 100 lbs. per square inch to the action of oxygen in the presence of a solid catalyst comprising aluminum phosphate and copper oxide.

5. The process as defined in claim 1 in which the reaction takes place at a pressure above 200 lbs. per square inch.

6. A process of treating a normally gaseous olefin hydrocarbon to produce valuable liquid products, which comprises subjecting the olefin at a temperature in the range 400-1000 F. to the action of a mixed solid catalyst'comprising aluminum phosphate and copper oxide. 

